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This paper is concerned with the ideal theory of a commutative ring R. We say R has Property (α) if each primary ideal in R is a power of its (prime) radical; R is said to have Property (δ) provided every ideal in R is an intersection of a finite number of prime power ideals. In (2, Theorem 8, p. 33) it is shown that if D is a Noetherian integral domain with identity and if there are no ideals properly between any maximal ideal and its square, then D is a Dedekind domain. It follows from this that if D has Property (α) and is Noetherian (in which case D has Property (δ)), then D is Dedekind.

Major depressive disorder (MDD) is commonly chronic and/or recurrent. We aimed to determine whether a chronic and/or recurrent course of MDD is associated with acute and longer-term MDD treatment outcomes.

Method

This cohort study recruited out-patients aged 18–75 years with non-psychotic MDD from 18 primary and 23 psychiatric care clinics across the USA. Participants were grouped as: chronic (index episode >2 years) and recurrent (n=398); chronic non-recurrent (n=257); non-chronic recurrent (n=1614); and non-chronic non-recurrent (n=387). Acute treatment was up to 14 weeks of citalopram (⩽60 mg/day) with up to 12 months of follow-up treatment. The primary outcomes for this report were remission [16-item Quick Inventory of Depressive Symptomatology – Self-Rated (QIDS-SR16) ⩽5] or response (⩾50% reduction from baseline in QIDS-SR16) and time to first relapse [first QIDS-SR16 by Interactive Voice Response (IVR) ⩾11].

Results

Most participants (85%) had a chronic and/or recurrent course; 15% had both. Chronic index episode was associated with greater sociodemographic disadvantage. Recurrent course was associated with earlier age of onset and greater family histories of depression and substance abuse. Remission rates were lowest and slowest for those with chronic index episodes. For participants in remission entering follow-up, relapse was most likely for the chronic and recurrent group, and least likely for the non-chronic, non-recurrent group. For participants not in remission when entering follow-up, prior course was unrelated to relapse.

Conclusions

Recurrent MDD is the norm for out-patients, of whom 15% also have a chronic index episode. Chronic and recurrent course of MDD may be useful in predicting acute and long-term MDD treatment outcomes.

Optical and structural properties of InGaN/GaN quantum wells having growth interruption were investigated using high-resolution x-ray diffraction, photoluminescence and transmission microscopy. InxGa1−xN/GaN (x>0.25) six pair quantum wells used in this study were grown on c- plane sapphire by metalorganic chemical vapor deposition. The growth interruption was carried out by closing the group-III metal organic sources before and after growth of InGaN quantum well layers. With increasing the interruption time, the quantum dot-like region and well thickness decreases due to indium re-evaporation or thermal etching effect. As a result, PL peak position is blue-shifted and intensity is reduced. The size and number of V-defect did not vary with interruption time. The interruption time is not directly related with formation of the defect. The V-defect in quantum wells originates at threading dislocations and inversion domain boundaries due to higher misfit strain.

InAs quantum dots were grown on GaAs substrates at various coverages and capped after varying the time of growth interruption. The evolution of this system was examined by correlating photoluminescence and transmission electron microscopy measurements. Results show for the first time the growth interruption to be a critical factor in generating defect-free quantum dot ensembles at coverages well above established metalorganic chemical vapor deposition coverage window for defect-free, Stranski-Krastanow self-organized growth. In addition, our results also support the absence of a stable, dislocation free 3D state and that the chemical potential eventually drives the system towards dislocated quantum dot clusters.

Radio frequency (RF) diode sputtering has been used for the growth of giant magnetoresistive (GMR) metal multilayers. Control of the atomic-scale structure of the surfaces and interfaces within these films is critical for GMR applications. A systematic series of experiments have been conducted to evaluate the dependence of the magnetotransport properties upon the growth conditions (i.e. background pressure, input power) for NiFeCo/CoFe/CuAgAu spin valves during RF diode sputter deposition. By using computational fluid dynamics, plasma, molecular dynamics, and various Monte Carlo techniques, a multiscale modeling approach has investigated the atomic assembly events during film growth. Energetic metal atoms and inert gas ion fluxes are shown to have very strong effects upon interfacial structures. The insights gained have led to novel deposition strategy propopositions for interface morphology control.

We have investigated the effect of chamber pressure and atmosphere on the microstructure and nanomechanical properties of amorphous diamondlike carbon (DLC) thin films prepared by pulsed laser deposition. The amorphous carbon films were deposited in various atmospheres such as nitrogen and argon at different pressures. We used Raman spectroscopy and optical microscopy to study the bonding characteristics and microstructures of the DLC films. Nanoindentation measurements were carried out on various samples prepared under different conditions to study the effect of chamber pressure and atmosphere on the elastic modulus and nano-hardness of the films. It was found that reduced vacuum leads to softer amorphous carbon films. Amorphous carbon films prepared in higher pressures exhibit increased density of particulates, and significantly rough surface. The results were understood in terms of thermalization of the laser plasma due to increased possibility of collision.

We have succeeded in the synthesis of strong Cu(111) textured films by means of the novel ion plating method(URT-IP). This URT-IP method combines the Cu deposition with the surface cleaning (self-cleaning). In the Cu film synthesis, the cations play a main role: the self-cleaning of underlying Cu seed and TaN barrier surfaces at the first stage of Cu deposition and the promotion of (111) texture. The two growth processes dependent on underlying materials cause the strong (111) orientation; the epitaxial growth on the same (111) oriented underlayer and the promotion of thermodynamically stable (111) texture on the amorphous underlayer. The in-situ Ar+ cleaning of underlayer surfaces by the URT-IP improves the (11) orientation to be much stronger. The URT-IP method is applied also to the synthesis of strong Pt(111) textured films with the same fcc system.

Thin films can be deposited with atomic layer control using sequential surface reactions. The atomic layer deposition (ALD) of compound and single-element films can be accomplished using the appropriate surface chemistry. This paper reviews the ALD of dielectric alumina (Al2O3) films and conducting tungsten (W) films. The Al2O3 films are deposited on submicron BN particles and the surface chemistry is monitored using Fourier transform infrared (FTIR) spectroscopy. Additional transmission electron microscopy (TEM) studies investigated the conformality of the Al2O3 growth on the BN particles. FTIR investigations of the surface chemistry during W ALD are performed on nanometer-sized Si02 particles. Additional in situ spectroscopy ellipsometry studies of W ALD on Si(100) established the W ALD growth rates. Al2O3 and W ALD both illustrate the potential of ALD to obtain conformal and atomic layer controlled thin film growth using sequential surface reactions.

We have used the embedded-atom method (EAM) to perform molecular-dynamics (MD) simulations of iron films grown on Cu (111). The iron atoms were randomly deposited, one at a time, above the surface just within the force range of the nearest surface atom. The growth mode is discussed by following the iron film coverage for an incident-atom energy ranged from 0.5eV to 15eV. A transition from island to layer by layer growth is observed as a function of incident energy. The effect of deposition rate is also studied.

A new fully three dimensional (3D) ballistic deposition simulator 3D-FILMS has been developed for the modeling of thin film deposition and structure. The simulator may be implemented using the memory resources available to workstations. In order to illustrate the capabilities of 3D-FILMS, we apply it to the growth of engineered porous thin films produced by the technique of GLancing Angle Deposition (GLAD).

Superconducting YBCO/YSZ/Hastelloy tapes or coated conductors were fabricated by combining ion beam assisted deposition (ILBAD) and magnetron sputtering techniques. The degree of biaxial alignment of the YSZ buffer layers and the epitaxial YBCO films was determined from x-ray pole figures and ø-scans. The best YSZ buffer layers had FWHFM δø= 7°- 10°. The corresponding YBCO tapes achieved a similar degree of biaxial alignment and high critical current density, Jc(77K,0T) = (0.9 – l.25)×106 A cm−2.

Scanning probe microscopy has yielded extraordinary advances in our ability to characterize surfaces at the atomic scale. These advances are paralleled by improvements in computational methods and platforms that now yield realistically complex multi-scale models of deposition processes. Combining these developments, it might now be possible to sense the dynamic state of an atomic surface, consulting with models to analyze the path of a deposition process. This real-time information might allow us to tweak the growing materials towards particularly unique and desirable final configurations. What we are largely missing are sensors that can monitor atomic scale evolution without, themselves, compromising the commercial deposition process. In a manufacturing environment, sensors cannot shadow the deposition process or contaminate the material. They cannot add significantly to the complexity of the deposition tool nor require that tool's extensive redesign. Importantly (at least over the long term) the sensors cannot even require us, that is, highly trained (and paid) individuals to operate and interpret their data!

We have developed a vapor deposition method that produces a highly ionized transient plasma plume of metallic species in the presence of a low-pressure inert or reactive gas glow discharge. In this process, a transient electrical discharge is formed in a hollow-cathode by a pulse-forming network (PFN) which is triggered by a pulsed CO2 laser. Current pulses with peak currents of 100 kA and pulse widths of about 20 ms have been produced by the PFN. The effect of the PFN power input and the ambient gas pressure on the evaporated material yield is presented. These experiments also showed a higher evaporation rate of carbon in a nitrogen ambient than in an Ar ambient. Carbon films, with rates of deposition exceeding 18A per pulse that are uniform over a large area, have been deposited. The ionic content of the plasma, spatial distribution of ions, and plume expansion dynamics have been investigated by time-of-flight ion probe measurements and optical emission spectroscopy and are presented.

Two major problems associated with Si-based MEMS devices are stiction and wear. Surface modifications are needed to reduce both adhesion and friction in micromechanical structures to solve these problems. In this paper, we will present a process used to selectively coat MEMS devices with tungsten using a CVD (Chemical Vapor Deposition) process. The selective W deposition process results in a very conformal coating and can potentially solve both stiction and wear problems confronting MEMS processing. The selective deposition of tungsten is accomplished through silicon reduction of WF6, which results in a self-limiting reaction. The selective deposition of W only on polysilicon surfaces prevents electrical shorts. Further, the self-limiting nature of this selective W deposition process ensures the consistency necessary for process control. Selective tungsten is deposited after the removal of the sacrificial oxides to minimize process integration problems. This tungsten coating adheres well and is hard and conducting, requirements for device performance. Furthermore, since the deposited tungsten infiltrates under adhered silicon parts and the volume of W deposited is less than the amount of Si consumed, it appears to be possible to release stuck parts that are contacted over small areas such as dimples. Results from tungsten deposition on MEMS structures with dimples will be presented. The effect of wet and vapor phase cleans prior to the deposition will be discussed along with other process details. The W coating improved wear by orders of magnitude compared to uncoated parts. Tungsten CVD is used in the integrated-circuit industry, which makes this approach manufacturable.

There is a great deal of interest in thin film deposition techniques which can achieve good crystal quality at low substrate temperatures. Pulsed laser deposition (PLD), well-known as a reliable technique for fabrication of high critical temperature superconductor thin films, has a number of characteristics which may make it suitable for such applications. In particular, PLD is characterized by a relatively large average species energy, which can be controlled by the laser fluence at the target. This paper describes the growth of silicon on silicon films using PLD over substrate temperatures between 500 and 700 °C, and in-situ characterization using reflection high-energy electron diffraction (RHEED). Transmission electron microscopy confirms the growth of single crystal oriented films, and atomic force microscopy indicates smooth films with an rms surface roughness of less than 2 Å

α-Alumina films are useful for high-temperature, wear, and semiconductor device applications because of their good oxidation resistance, high hardness values, and electrical properties. α-Alumina films have been previously synthesized using techniques such as chemical vapor deposition, sol-gel, physical vapor deposition, and plasma spraying. This paper presents an alternative approach for producing high quality dense α-alumina coatings using a flame-assisted process called combustion chemical vapor deposition (CCVD). This process is an open atmosphere technique that does not require the use of a reaction chamber. In this work alumina films were grown on YSZ at temperatures ranging from 900 to 1500°C. At lower temperatures only amorphous alumina was grown, but as the deposition temperature increased different alumina phases were formed. At 1100°C, a thin highly crystalline θ-Al2O3 coating was formed. At temperatures higher than 1100°C thick θ-Al2O3 coatings were deposited on the YSZ. Coatings were characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD).

A novel quasi-thermodynamic approach is suggested to simulate surface chemistry in III-V compound MOVPE. Blocking of free adsorption sites by methyl radicals is considered as the mechanism limiting the growth rate at low temperatures. This assumption has provided a good reproduction of experimental data on GaAs MOVPE in various types of reactor. The commercial computational fluid dynamics software CFD-ACE™ has been used to perform a detailed threedimensional modeling of AlGaAs and InGaP deposition in an AIX-200 horizontal reactor. The surface model has been incorporated into the code to obtain the growth rate and layer composition distributions over the substrate. Modeling results demonstrate a reasonable agreement with experimental data.

Crystalline titanium dioxide films were deposited on silicon (100) at temperatures as low as 184°C using the volatile molecular precursor, tetranitratotitanium(IV). Deposition rates in a low pressure chemical vapor deposition (LPCVD) reactor operated at 230 – 500°C with a precursor vessel temperature at 22°C were typically 4 nm/min. The effect of deposition temperature and annealing conditions on morphology are shown. Following post-deposition annealing in oxygen and hydrogen, Pt/TiO2/Si/Al capacitors were fabricated and exhibited dielectric constants in the range of 19 – 30 and leakage current densities as low as 10−8 Amp/cm2.

Advanced materials processing involves active control of fabrication and real-time monitoring of the final product. Sensors must be an integral part of the overall material processing system. ITN Energy Systems, Inc. and the Colorado School of Mines have developed a Parallel Detection, Spectroscopic Ellipsometer (PDSE) sensor for in-situ, real-time characterization and process control of multi-layered vapor deposited films. By measuring changes in the polarization state of reflecting light as a function of wavelength (250 to 5000 nm), the PDSE sensor determines the complex reflectance and/or the ellipsometric amplitude and phase. The PDSE provides cost-effective in-line sensing for film process control through detection of critical product variables that directly relate to film performance including: film thickness, optical excitation states, impurity concentrations, conductivity/resistance, intermixing at interfaces, microstructure, surface roughness, void fraction, defects, and grain size. The PDSE sensor is an optical probe with no moving parts that can measure the optical properties of thin films in as little as 3 msec with sensitivity to films less than a monolayer in thickness. We will use this PDSE system to provide real time process control of vapor deposited CuInGaSe2 (CIGS) films on a continuous flexible substrate. Initial results from CIGS films indicate that the PDSE has the sensitivity and accuracy to provide intelligent process control. The remaining challenge is to develop interpretive algorithms; the amount and quality of information required will determine their complexity. In addition, with the inception of in-situ, real-time monitoring, we hope to enable minimal data analysis approaches1 that provide extremely useful information with minimum interpretive algorithm development.

For purpose of enhancement of mechanical properties, Al/Al2O3 films, with thickness A in the nanometric scale, were deposited on silicon substrate by reactive rf sputtering, at substrate temperatures Ts ranging from −90°C to 600°C. The characterisation (FEG-SEM, AFM, SIMS, XRR) has shown that Al/Al2O3 films are granular and rough, in correlation with the behavior of single alumnium films. The minimal roughness values are obtained at low Ts (−90°C and 25°C). The Λ = 20 rim-films are real multilayers, as confirmed by SIMS and XRR. Nevertheless, the multilayering character, i.e. the existence of multilayers, decreases when Ts increases. At low Ts, the relevant parameter to explain the weakness of stratification of Al/Al2O3 films is the roughness of layers, while at high Ts, the chemical interdiffusion clearly dominates, resulting in a no periodic structure at Ts = 600°C.